Sorry to bring up such an old post, but I have some serious questions on how a butterfly can evolve.
I could buy the fact that the caterpillar stage evolved from a lower species except for the fact that caterpillars are incapable of reproduction. Even if they once were capable of reproduction and lost that ability after they evolved the rest of the way to a butterfly, one would think that the evolution process would end when the creature dissolves into liquid mush inside its chrysalis (or cocoon for other such creatures). Then it would have to undergo millions of years worth of evolution in just a few days or weeks before it rots. It has to evolve from a worm like creature with no real legs, simple eyes, and chews its food to a completely different creature with six long segmented legs, very complex eyes, wings with the ability to fly and navigate and a tube to suck nectar instead of chewing food.
All of that DNA would have had to be in place before it built its cocoon and since it never had a reason before, how did it evolve ?
The only other explanation I can think of is if the butterfly evolved first, but wouldn't giving birth to a worm be backwards evolution ? Even so, it would still need to overcome the problem of the DNA needed to complete metamorphosis. What would be the evolutionary process to develop it ?
Is it possible that the metamorphosis started at the single cell stage and both halves were able to evolve independently and still stay in perfect harmony with each other for billions of years, relying on each other for survival and reproduction ?

Horizontal gene transfer is the transfer of genes that do not happen during reproduction. see the vertical transfer as the one between generations, and the horizontal as a transfer that do not need reproduction. It is the case for acterial mating, but the gene transfer by viruses to build GMO also belong to this category.

Patrick

Science has proof without any certainty. Creationists have certainty without
any proof. (Ashley Montague)

I have done a little research on google about horizontal gene transfer and some of the stuff I read seemed to refer to transferring genes from past generations. As pertaining to this topic, would it be fair to assume that the caterpillar evolved directly into the butterfly first, then developed the metamorphosis stage later using old info from the original evolutionary process ?

burninbriar wrote:I have done a little research on google about horizontal gene transfer and some of the stuff I read seemed to refer to transferring genes from past generations. As pertaining to this topic, would it be fair to assume that the caterpillar evolved directly into the butterfly first, then developed the metamorphosis stage later using old info from the original evolutionary process ?

Hmm.... interesting....

It is seen that many Dipteran flies deposit there egg in caterpillars; so may be this is cause of gene tranfer some time and got new generation to evolve...

Senior Education Officer, BNHS, India. www.bnhs.org

Bitter Truth!Who says reason for world war IV will be Petrol? Reason lies in two words "Me and Mine".

I've been going over this a lot and I can see where the horizontal gene transfer could account for a butterfly possibly having an egg hatch a baby caterpillar instead of a butterfly but that would still not account for the DNA required to make the caterpillar dissolve and reconstitute its self back into a butterfly. The only logical conclusion I can come up with is that the DNA for metamorphosis was formed when the first cell was formed. Does any one know if that DNA code for metamorphosis has been identified and if so, has it or anything resembling it been seen in other simple life forms ?

Start with a winged insect, using some brief seasonal food source. To get from season to season, it uses eggs. The eggs hatch and the nymphs resemble the adults, quickly going through the stages to get there. As is generally true, the nymphs are not winged, and feed on the seasonal food source.

Occasional mutations may hatch the eggs early, or produce nymphs that are still somewhat embryonic, more like segmented egglets, but with some developed body parts, such as mouthparts and legs (this is not far off describing the larval stages of indirect developers). This alone would not probably be advantageous, unless combined with an ability to eat food other than the adult fare - those variants could hatch early, feed and grow, and be adults when the "real" food source becomes available (giving a pretty decent advantage to those adults, and somewhat isolating them reproductively). They would need to be able, in the next-to-last molt, to be able to become functional, winged, reproductive adults.

If this type of life cycle is successful enough, evolutionary pressures now exist on all stages, but since they fill different niches, their specialties will make them more and more specialized. You look today at the caterpillar-pupa-butterfly sequence, and it seems impossibly complex, but you just need a hint of it at the beginning you get you there. It's all hypothetical, of course, but plausible, and there are probably several other plausible scenarios as well.

Thanks for the direction, I still haven't had a chance to research it as much as I want, but I will. I was actually thinking more in the line of a single cell organism though.

Hay Darby;
Thats an interesting scenario, I need to think about this one some more. Although I see where you explain the stages, I still can't get over the part where the caterpillar dissolves and then reconstitutes its self. I'm going to ponder you're scenario some more.

Start with a winged insect, using some brief seasonal food source. To get from season to season, it uses eggs. The eggs hatch and the nymphs resemble the adults, quickly going through the stages to get there. As is generally true, the nymphs are not winged, and feed on the seasonal food source.

Occasional mutations may hatch the eggs early, or produce nymphs that are still somewhat embryonic, more like segmented egglets, but with some developed body parts, such as mouthparts and legs (this is not far off describing the larval stages of indirect developers). This alone would not probably be advantageous, unless combined with an ability to eat food other than the adult fare - those variants could hatch early, feed and grow, and be adults when the "real" food source becomes available (giving a pretty decent advantage to those adults, and somewhat isolating them reproductively). They would need to be able, in the next-to-last molt, to be able to become functional, winged, reproductive adults.

If this type of life cycle is successful enough, evolutionary pressures now exist on all stages, but since they fill different niches, their specialties will make them more and more specialized. You look today at the caterpillar-pupa-butterfly sequence, and it seems impossibly complex, but you just need a hint of it at the beginning you get you there. It's all hypothetical, of course, but plausible, and there are probably several other plausible scenarios as well.

You are fabulous; Im going to search that more now.......

Senior Education Officer, BNHS, India. www.bnhs.org

Bitter Truth!Who says reason for world war IV will be Petrol? Reason lies in two words "Me and Mine".